Method and means for producing closed end tubing



Li) M Dec; 22,1953 R. 1.. WHlTlNG El AL 2,663,206

METHOD AND MEANS FOR PRODUCING CLOSED END TUBING Filed March 15 1950 2 Sheets-Sheet l IN V EN TORS' Poss/P75 WWI/N6 PIC/YARD A. WWW/v66 Dec. 22, 1953 wH|T|NG AL 2,663,206

METHOD AND MEANS FOR PRODUCING CLOSED END TUBING Filed March 15 1950 2 Sheets-Sheet 2 INVENTORS ATTORNEY Patented Dec. 22, r 1953 truce Arc in us not neo rene M w QLQEQ 'IDQQL Richard L. Whiting. and Robert 'Whiting, Detrait, Mich," assixngrs to. Win'tins 89!! ets. ncorporated. a merstion Mic nsen eminence Ma ni i 9, sr al 14 ,199

.Glaims.

vide an improved; effective and positive method and means for producing closed end tubing by combined centrifugal and axial deformation fur, ther combined with extreme metal working at a critical portion of the forming operation and relatively minor metal working before and after the critical portion of the forming operation.

Another object of the invention is to provide an improved, eifective and positive method and means for producing closed end tubing, including the steps of trictionally pre-heating the end of the tubing in a pro-heat ring, slightly working the tubing while frictionally increasing the tern perature thereof in an initial heat and forming zone'simultaneousl-y with starting to close the end thereof, heavily working of the tubing while fricr tionally further increasing the temperature thereof in a forming heat and. major forming zone simultaneously with nearly closing the end there.- offand then frictionally further increasing the said heat of the tubing in a final forming zone while gradually reducing the working thereof to zero working near the center of the tube, and frictionally increasing the temperature at the end of the tubing to a point of fusion while close ing the end thereof in a finishing zone at the center of the tube without further Worlging.

Gther objects of the invention will become ebirus by efe n e t th o wi e i e deosrirti n. when n connection wit the e ompeering rawings which; Fig. 1 is a view in perspective showing a nae hiee o he neral tim on the me h .15 ro uci closed teeming: mey be erecting ll wlz they emr qr the ee qu ar m ans and eceenn 's he m t Qt t bin We 2 ve tical seo ieealview Qt ar ai ned and im roved die, enamored o ca ryin out the method steps. embodying the invention, a tube having had its end closed the; said die being positioned therein. V Fig. 3 is an end elevational view taken on the (Cl. He-89 all) . 2. line Se-,3 of Fig. 2 with-the tube omitted showing a preferred form of ribbing of the .die cavity.

Fig. i is an enlarged --frag=mentary sectional view taken on the line'44 of Fig. 2 showing the par-.- tigrrlar die ribbing preferred in the initial heat zone.

Fig. 5 is an enlarged fragmentary sectional view taken on the line 4 -4 of Fig. 2 showing the par-.- ticular die ribbing preferred in the critical forming heat zone.

Fig. 6 is an enlarged fragmentary sectional view taken on the line 61-6 of Fig. 2 showing the par.- ticular die ribbing preferred in the final form.- i-ng zone.

Fig. 7 is an enlarged fragmentary sectional view of the constmiction shown in the dot and dash circle 1 of Fig. 2 modified to indicate how the center of the die would he formed to provide an open neck at the center of the closed end tubing.

The term "closed end tubing as herein em-. ployed means the generally domed shape end formed on a metal tube of steel, copper, bronze or other material which will flow plastically responsive to frictional heat and metal working. The end of the tube need not be completely closed to come within the term closed end tubing as herein employed. I

Referring now to the drawings wherein like numorals and reference characters refer to like and corresponding parts throughout the several views, the tube ending machine disclosed in Fig. 1 is illustrative of the type of machine that may include the means and carry out the method of producing closed and tubing embodying the invention. The particular machine for closing the ends of tubing disclosed for illustrative and not limiting' purposes comprises a base H], a bed H, a hydraulically operated tube clamping fixture I2 fixed to the center of the bed H, a pair of ways 13 onto which platens ll are slidably mounted, a pair of oppositely disposed axially aligned electric motors 5' each mounted on one of the platens it, each electric motor l5 having a chuck I6 mount ed on the drive shaft E50 thereof, a tube closing die 30 fixed in each or said chucks l6 for rotation therewith, a hydraulic cylinder I! for clamping a tube 25 to be closed at its ends in the tube clamping fixture I2, hydraulic cylinders l8 supported on an extension I 9 of the bed H for advancing the platens 14 against a central stop 20 whereby to advance the dies 39 a predetermined distance against the open end of a tube 25 to close the same as hereinafter described in detail. Stops 2| on the platens l4 engage stops III) on the ways B to limit the outward trace! at the platens Start button S is pressed which starts both t motors (5 which rotate the dies 30. The hydraulic tube clamping fixture I2 is open, a tube to have its ends closed is placed therein, and the Clamp button 0 is pressed which causes the hydraulic cylinder I! to clamp the said. tube 25 and hold it in axial alignment and non-rotat ably with respect to the rotating dies while the hydraulic cylinders l8 advance the platen I l toward the center of the machine and against the central stop 28 whereby to advance the dies 38 a predetermined distance onto opposite ends of the tube 25 in the process of having its ends closed. As soon as the foregoing cycle of operation is completed, the movement of the hydraulic cylinders i8 is reversed thereby reversing the platens l4 automatically, the tube clamping hydraulic cylinder H of the tube clamping fixture i2 is then reversed whereby to release the tube 25 having had its ends closed, and another tube '25 to have its ends closed is then placed in the machine and the cycle is repeated. The Emergency button E is pressed by the operator of the tube ending machine in the event it becomes necessary to stop the machine during its automatic operating cycle.

Inasmuch as the details of the construction of the tube ending machine illustrated in Fig. 1 and the controls therefor are obvious to those skilled in the art, the tube ending machine will not be described in detail. However, the improved method of producing closed end tubing and the novel means for accomplishing the said method is best illustrated in the construction, formation and function of the dies 30 and their application to tubing 25, all hereinafter fully de scribed in detail.

Referring now particularly to Figs. 2-6 inclusive, the tube closing die 30 is seated in the die cavity 155 of the chuck l6 and is fixed in nonrotatable relationship with respect thereto by such means as the pins 22. The die 3!! is provided with a generally semi-spherical shaped tube cavity 3| formed therein starting at the annular face 32 of the said die 30 with an annular tapered lead. 23 for guiding the open end of tubing 25 to be closed into a pro-heat ring A which is substantially the same internal diameter as the external diameter of the tubing 25. Inwardly and blending from the pre-heat ring A is formed a pair of oppositely disposed ribs 34 contoured with their highest point disposed on the longitudinal axis of the tube 25 and describing the external domed shape of the closed end 250 of the tube 25 when closed, the said oppositely disposed ribs 34 blending into the base of the tube cavity 3! at the center or finishing zone E of the said die 33. It will be noted that the depth of the generally semi-spherical tube cavity 3| below the high point of the ribs 32 beginning at the inner edge of the pre-heat ring A and ending at the finishing zone E is such as to establish an initial heat and forming zone. B, a forming heat and major forming zone C, and a final forming zone 4 D adjacent the said finishing zone E. It will be further noted that the cross sectional configuration of the ribs 34 preferably varies gradually from a fiat wide rib 34! in the initial heat and forming zone B, to a relatively deep wide rib 342 in the forming heat and major forming zone C,

and to a narrower and shallower rib 343 in the final forming zone D fading out to an un-ribbed surface in the finishing zone E.

Obviously zones A to E inclusive are subject to variations as to the extent thereof as well as are the conformations of the ribs 32 at each of the zones 13, C and D; however, the improved, effective and positive method and means for producing closed end tubing herein disclosed contemplates the generation of heat in the end or ends of tubing 25 being closed combined with limited working of the tubing 25 in a more or less degree at the several zones as the rotating die or dies 30 are pressed over the end or ends of the non-rotating tubing 25 as the said end or ends of the tube 25 are being closed.

The method and means for closing the end or ends of tubing embodying the invention will be better understood by describing that which takes place when a tube 25 to be closed at its end is attacked by a rotating'specially formed die 35. In the particular example given as illustrative of the invention, the die 36 is preferably rotated at approximately 3600 R. P. M. The rate of advance of the die 38 onto the open end of the nonrotating tube 25 varies according to the type of material employed in and thickness of the tube 25, which rate of advance is adequate to provide sufficient heat in the end of the tube 25 when attacked by the inner half of the forming heat zone D to bring the temperature of the said tube 25 to just below melting point making the end of the tube 25 thereat substantially plastic and maintaining the temperature to maintain the substantial plasticity of the end of the tube 25 through the final forming zone B and the finishing zone E where the advance of the die 32 onto the tube 25 ceases whereupon the closed end of the tube 25 cools suificiently to permit a final set of the metal thereof while the die 36 is still rotating but not advancing, the die 38 then being withdrawn from over the end of the tubing.

If complete closing of the end 255 of the tubing 25 is not desired, the rotating die 32 is advanced slightly less than normally required to fully close the end 258 of the tubing 25 whereupon an insumcient amount of metal is present at the center of the substantially closed end 252 of the tubing 25 to fully close the same. Also, as shown in Fig. 7,,if an open neck 35 or any other annular form is required at the axial center of the closed end 250 of the tubing 25, the tube closing die 35 is formed to correspond by providing, as in the example given, a central slightly tapered cylindrical nib 35 and an annular well 3? adjacent thereto into which metal from the nearly closed end 255 of the tube 25 flows to form the said open neck 35.

Referring again particularly to Figs. 2-6 inclusive, when a straight tube 25 is attacked by the rotating tube closing die 39, the annular tapered lead 33 thereof encompasses the annular end of the said straight tube 25. As the rotating tube closing die 30 advances further, the end of the straight tube 25 is frictionally engaged by the pre-heat ring A which elevates the temperature of the end of the said tube 25 to a temperature somewhat below cherry red. As the rotating tube closing die 30 advances further onto the end of the straight tube 25, the ribs 34 thereof at the initial heat and forming zone B further elevate the temperature of the end of the tube to slightly below cherry red as the end of the tube takes its initial forming. As the rotating tube closing die advances further onto the end of the tube 25, the ribs 34 thereof at the forming heat and major forming zone C further elevate the temperature of the end of the tube to or sightly above cherry red but below the point of fusion as the end of the tube takes its major forming. As the rotating tube closing die 30 advances further onto the end of the tube 25, the ribs 34 thereof at the final forming zone D maintain the temperature of the end of the tube at above cherry red but below the point of fusion as the end of the tube takes its final forming. As the rotating tube closing die 30 advances further and to its maximum advance onto and over the end of the tube 25, the smooth surface thereof at the finishing zone E frictionally heats the end of the tube to a state of plasticity and fusion as the end of the tube is closed or is substantially closed.

The term somewhat below cherry red, slightly below cherry red, cherry red, above cherry red but below the point of fusion, and a state of plasticity and fusion as herein used are all relative heat terms employed because the actual specific temperatures to which the end of the tube 25 is elevated as the rotating tube closing die 30 is advanced onto and over the end thereof cannot be measured accurately; however, by observation of tubes 25 from which the rotating tube closing die 30 has been withdrawn quickly at check points in the advanceof the said rotating tube closing die 30 thereover, indications are that the hereinbefore stated relative heating of the end of the tube 25 occurs during the formation of a completely or substantiall completely closed end 250.

As the rotating tube closing die 30 is advanced over the end of a tube 25 to be closed thereby, the said tube 25 is worked by the pressure of the oppositely disposed generally axially extending ribs 34 of the said tube closing die 30 being urged thereagainst, the resistance of the said tubing 25 against being deformed from a straight piece to a completely or substantially completely closed end 250 by the oppositely and axially disposed ribs 34 of the said die 30, which resistance increases as the tubing 25 gradually becomes closed, permits the said ribs 34 to indent themselves minutely and progressively into opposite sides of the tubing 25 as the end of the said tubing 35 is closed by the advancement of the said rotating tube closing die 30 thereover and thereonto, thus working the tubing 25 closed at its ends. The pressure of the attack of the tube closing die 30 against the end of the tube 25 being closed and the rate of advance of the said tube closing die 30 over the said end of the tube 25 being closed depends upon the diameter and wall thickness of the tube 25. The pressure of attack or thrust pressure of the tube closing die 30 always must be suificient to maintain a constant or continuous pressure'on the end of the tube 25 coupled with the proper rate of advance of the tube closing die 30 onto the end of the tube 25 to raise the temperature of the end of the said tube 25 during the tube closing operation to approximately those temperae tures hereinbefore described.

It has been found that two ribs 34 in the tube ameter having up to 4;" wall thickness. For

some tube ending operations, particularly although not exclusively in larger diameter tubing, three or even four ribs 34 may be required to provide the proper working of the tube end during the closing of the tube. While it has been discovered that the ribs 34 preferably vary gradually in cross sectional configuration from a relatively wide fiat rib as indicated in Fig. 4, to a relatively deep wide rib as indicated in Fig. 5, to a relatively shallower narrow rib as indicated in Fig. 6 which fades out in the finishing zone E as indicated in Fig. 2, it is contemplated that the rib configuration may be varied to suit particular conditions of various tube ending production operations where the problem is not normal, as for example, when the closed end 255 is required to be other than substantially dome shaped.

Although but a single embodiment of the invention and a single example of the method steps have been disclosed in detail, it is obvious that many changes may be made in the size, shape,

detail and arrangement of the elements of the invention and that variations may be made in the method steps employed, all without departing from the spirit and scope of the invention as defined by the appended claims.

We claim: 7

1. A tube closing die comprising a die block having an annular substantially smooth preheat ring whose diameter is substantially the same as the diameter of a tube to be ended thereby and a generally semi-spherical shaped imperforate cavity inwardly of the said annular v pre-heat ring, and a plurality of axially disposed straight ribs extending above the surface of the said cavity, each rib being deepest at approximately the center thereof and fading out at the pre-heat ring and near the center of the die, the said ribs being relatively flat and shallow beginning at a point inwardly of the face of the die,

, relatively deep and wide at the longitudinal central portion thereof, and relatively shallow and narrow at the portion thereof fading out near the center of the die.

2. A tube closing die comprising a die block having an annular substantially smooth pre-heat ring whose diameter is substantially the same as the diameter of a tube to be ended thereby and a generally semi-spherical shaped imperforate cavity inwardly of the said annular pre-heat ring, and a plurality of generally axially disposed straight ribs extending above the surface of the said cavity, each rib being deepest at approximately the center thereof and fading out at the pre-heat ring and near the center of the die.

RICHARD L. WHI'I'ING. ROBERT E. WHITING.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 84,907 Ritter Dec. 15, 1868 172,443 Ide Jan. 19, 1876 1,297,819 Ferrier Mar. 18, 1919 2,434,737 Enghauser Jan. 20, 1948 2,524,420 Blampin Oct. 3, 1950 

